recently I came across "whistled languages", of which there still exist between 60 and 90. Of course I knew about them, but I did not think of them in conjunction with ISO 639.
But in archives with audio language data whistled documents occur, whose language has to be identified. To some extent the relation between a spoken language and its whistled form resembles to the relation between a language and its sign language.
Would it be sufficient to have just one generic code for the whistled form of a language, or may there be dialects and other variants?
What is your opinion?